1. Field of the Invention
Embodiments of the present invention generally relate to network traffic management.
2. Description of the Related Art
Quality of Service (QOS) generally refers to a measure of performance for a transmission system that reflects its transmission quality and service availability. QOS is a major focus for network service providers, particularly as customers rely on the networks to offer applications that demand high reliability, such as streaming media applications and voice over internet protocol (VOIP) services. For example, for a VOIP connection, the focus is how to ensure packet traffic has a high enough priority to ensure it will not be delayed or dropped due to interference from other lower priority traffic.
In some cases, a priority may be assigned to a packet via a parameter in the packet header that designates a type of service (ToS), also referred to as a class of service (CoS). The ToS parameter may indicate how an upper-layer protocol requires a lower-layer protocol to treat its messages. The ToS field typically acts as a priority field that determines how the packet is handled relative to other packets. In some cases, a network device along a route may downgrade a packet by modifying the ToS field, for example, due to network congestion or as an incorrect re-marking by a service provider. Unfortunately, if the packet is downgraded by modifying the ToS, the packet may not have the same priority. As a result, there may be some delay in delivery of the packet, which may adversely affect the service, for example resulting in audible echoes in a VOIP application.
Accordingly, what is needed is a technique for detecting network congestion.